Method of and mechanism for trimming the doctor blade of a printing press



G. AL FRlEs METHOD OF AND MECHANISM FOR TRIMMING THE DOCTOR-BLADE OF A PRINTING PRESS Filed July 20, 1935 4 Sheets-Sheet l l Il ATTORNEY AWE@ 2g, i936. Gf A FRESS www METHOD OF AND MECHANISM FOR TRIMMING THE DOCTOR BLADE OF A PRINTING PRESS n p VENTOR f; w Y@ A ATTORN EY AWE 28,1936.

METHOD OF' AND MECHANISMFOR TRIMMING THE DOCTOR BLQDE OF A JRINTING PRESS Filed July 2o, 1955 4 sneetS-sheet 3 TTORNEYJ` G. A. FRIIESS Z- Amid 28, i936. e. A. FRnEss y 2,@399363 METHOD OF AND MECHAISM FOR TRIMMING THE DOCTOR BLADE OF A PRNTING PRESS d Filed July 20, 1935 4 Sheets-Sheet 4.

CCI( ff ATTORNEYS Patented Apr. 28, 1936 UNITED STATES PAT-ENT OFFICE METHOD F AND MECHANISM FOR TRIM- MING THE DOCTOR BLADE OF A PRINT- ING PRESS Gustave A. Friess, Rye, N. Y., assignor to News Syndicate Co. Inc., New York, N. Y., a. corporation of New York My invention relates to a new and improved method of, and apparatus for, trimming or shaping the doctor blades which are used in printing presses.

One of the objects of my invention is to provide an apparatus for trimming doctor blades which are madey of thin and flexible metal, about 0.010 inch thick, and which are used in rotary gravure printing presses. However, the invention is not limited to the use thereof on blades of any specied thickness. The blades may be made of heavy steel, having a thickness of 0.014v inch to 0.016 inch.

Another object of my invention is to provide an improved apparatus and method for trimming or shaping the edges of doctor blades which are very thin and flexible, so that said doctor blades have no substantial inherent rigidity.

In order to use such doctor blades, they must be mounted within a rigid holder, from which an edge portion of the doctor blade projects. It is preferred to have the doctor blade held under tension in said holder, in order to make it possible to use very thin and flexible steel or other material.

Another object of my invention is to provide a device of this type whereby a doctor blade made of thin and flexible material can have its edge accurately trimmed or shaped, without distorting the doctor blade from true planar form.

Another object of my invention is to provide an apparatus and method whereby the edge of the doctor blade can be trimmed without forming a burr of objectionable thickness, at the trimmed edge.

Other objects of my invention` will be set forth in the following description and drawings which illustrate a preferred embodiment thereof, it being understood that the above statementk of thek objects of my invention is intended to generally explain the same without limiting it in any manner.

Fig. l is a front elevation of a device made according to my invention.

Fig. 2 is a top plan view ofFig. 1.

Fig. 3 is a sectional view on the line 3-3 of Fig. 2.

Fig. 4 is an enlarged view similar to Fig. 3', but showing the parts in a different relative position.

Fig. 5 is an enlarged detail plan View of certain of the parts which are shown at the lefthand side of Fig. 2.

Fig. 6 is an enlarged detail plan view, of certain parts which are shown at the right-hand side of Fig. 2'.

Fig. '7'Y is a detail view of certain of the parts which are used for feeding the support upon which the shearing device and certain other parts are mounted.

Fig; 8 is an end elevation of the left-hand side` of Fig. 1'.

Fig. 9 is a detail View, illustratingv the action of the blades of the` shearing mechanism.

Fig. 10 isc an enlarged View showing certainv details of the cutting mechanism, and of certain associated. parts.

Fig; 1'1 is a sectional'view on the line IIL-II of Fig. 10.

Fig.. 12 is a sectional view showing a different embodiment of the mechanism for feeding the cutter.

The device consists generally of a frame F, at whose upper end a horizontal rack I is provided. The cutting device which is used forl trimming the blade, is mounted upon' a support S having a top member 2, and a bottom member 3. Said support may be made up of any desired number of parts.

The top member 2 is provided with a detachable guide member 2a, and the. bottom member 3 is provided with a detachable guide member 3a'. Said guide members. 2a and 3a. slidably Contactv with adjacent portions of the frame F.

A shaft 5 is turnably mounted in suitable bearings, Which are provided in the hollow support S. Said hollow support S can. have a U-shaped or rectangular cross section. The shaft 5 is turned by means of a hand wheel 6I. A worm 'I is provided upon the shaft 5, and this worm meshes with a gear which is provided on the vertical shaft 9. A gear I0, which is smaller than. the gear 8, is mounted upon the shaft 9, so that the gear I0 is turned by the shaft 5. The gear I0 mesheswith the rack I, so that the turning of the wheel 6 causes the support Sto move horizontally, to and fro.

A laterally movable lateral slide II is provided at the top of the support S.

The slide II' is guided between members I2, which are secured to member 2, as shown in Fig. 11'. Said slide II` is4 provided' with a standard I4', which supports4 a small electric motor' M. The slide II, together with the motor M, can. be laterally adjusted, by means of a hand wheel I5. This hand wheel I5 is connected to an externally threaded shank I5a. (see' Fig. 11.) having a collar which is mounted in a bearing. of member I 6, which is fixed to the movable support S. Said shank I5a has a collar, as shown in Fig. 11i, which prevents the longitudinal movement of said` shank. -rIhe threaded shank I5a of the wheel I5 passes through an internally threaded bore which is provided in the bottom of slide I, so that the slide I I is moved laterally to and fro, by the turning of said threaded shank I5a.

The trimming device comprises a first shear blade I1, which does not move, save to the extent that it is moved in unison with the slide I I and the support S. This shear blade I1 is rigidly connected to a holding member |1a. The holding member I1a is suitably connected to the casing of the motor M.

Referring to Fig. 9, this shows a blade I8 which is connected to a vertically movable holder I8a. The motor drives a shaft 29 by any suitable connectng means, which are not shown, as they may be of any conventional type. This shaft 20 is perpendicular to the motor shaft.

As shown in Fig. 9, the shaft 28 has an eccentric 2| which is located within an anti-friction bearing 22, comprising inner and outer races, having intermediate balls 23.

The holder I8a is of annular form and its inner surface contacts with the outer race of the ball bearing, so that the turning of the shaft 20 produces an up-and-down cutting movement of the blade I8. The shaft 20 also has enlargements or collars 24, which are shown in Fig. 9, and which are located within the inner annular races of additional ball bearings.

The outer races of said supplemental ball bearings are connected to the casing of the motor M.

Mechanism is also provided for cutting the steel strip which is used for making the doctor blades, into suitable lengths. This steel strip can be wound upon a suitable reel 30.

Referring to Fig. 2, a suitable length of the steel strip is unrolled from the reel 30, and this steel strip is laid upon a table 3|, until the end of the steel strip abuts the guide 32, which is fixed in suitable position upon the table 3|.

A cutting blade 34a is turnably mounted at 35h to the frame of the machine, and this cutting blade 34a is connected by means of a link 36 to a treadle 31a which is pivoted to the frame of the machine.

A spring 38 normally holds the cutting blade 34a, in the inoperative position shown in Fig. 8. The lower end of spring 38 is connected to the frame and the upper end is connected to link 36. The movable cutting blade 34a cooperates with the fixed cutting blade 39h, in order to cut the strip by a shearing action.

In order to maintain the doctor blade D under tension while its edge is being trimmed, said doctor blade is held, during said trimming operation, in a holder 34, in which said doctor blade D is inserted and held under suitable tension. Said holder 34 has two rigid plates or jaws, which can be forced into clamping position by clamping screws or bolts 35, which may or may not pass through doctor blade D. A stiffening strip D', which may be rigid or bendable, is also clamped between said jaws and blade D, by said clamping screws or bolts 35, which may or may not pass through said strip D.

In order to secure the initial tension of the doctor blade D within the holder 34, the holder 34 may be located in members 31, which are connected to a shaft 38, which is supported in suitable bearings in the frame of the machine. The screws or bolts 35 may be located between said members 31, so that screws or bolts 35 may be readily loosened and tightened. Said members 31 have clamping members 31h, for clamping the doctor blade D between the jaws of holder 34. Said holder 34 is longitudinally rigid but its jaws are laterally movable. Said holder 34 may be made of metal, and it may have separate jaws or it may have a U-shaped cross-section. Said clamping members 31h operate to force the jaws of holder 34 against doctor blade D and strip D. The members 31 can be moved to the vertical position indicated in Fig. 3, by turning shaft 38, and the clamping members 35 and 31h can then be loose. The ends of the doctor blade can then be engaged between pairs of jaws 39 and 39a.

As shown in Fig. 6, each jaw 39 is rigidly connected to a longitudinally movable rod 4I. As shown in Fig. l, each jaw 39 is provided with an extension 44 whose lower end is slidable in the groove of a guide member 45, so that the jaw 39 is guided in its longitudinal movement, and the jaw 39 is held against turning. The hinged jaw 39a is actuated to clamp one end of the doctor blade, by means of a member 48.

Each rod 4I passes through a collar 43 which is connected to a bracket of the frame. The outer end of each rod 4I is externally threaded.

A wheel 41 is provided with an internally threaded hub 48. A plate 49 is connected to each sleeve 43 and each plate 49 has a lip 50, which engages a corresponding circumferential groove of the hub 48 of the wheel 41. The wheel 41 is thus free to turn, but it cannot move longitudinally. By turning the wheels 41 while the ends of blade D are clamped between the pairs of jaws 39 and 39a, the doctor blade can be subjected to any suitable tension so that it is held straight and planar, while said blade and its holder are located in members 31.

While the blade D is held under said tension, the clamping members 35 and 31h can be tightened, so that the doctor blade is held under tension in the holder 34. After the doctor blade has been mounted and tensioned and clamped in holder 34 so that it is held under tension, the shaft 38 and the holder 34 are turned to the position indicated in Fig. 4, so that the doctor blade rests upon a support 52.

In order to turn the shaft 38 from the position illustrated in Fig. 3, to the position illustrated in Fig. 4, the shaft 38 is provided with a worm gear 19. This meshes with a worm 1I which is mounted upon a vertical shaft which is provided with a hand wheel 13 as shown in Fig. l and in Fig. 5.

In the embodiment shown in Fig. 12. I provide a worm drive for actuating the support S. In this embodiment the rack I is mounted underneath the adjacent portion of the frame F. The underside of the rack I is engaged by the pinion or gear which is mounted upon the shaft 8|. The shaft 8| has a gear 82 which meshes with the smaller gear 83, mounted upon the hollow shaft 84. 'I'he shaft 84 is actuated by a hand wheel 85.

In this embodiment the hand drive can be replaced by a machine drive if desired. For this purpose a shaft 86 is located within the hollow shaft 84.

At one end thereof the shaft 88 is connected to a head 81. As shown in Fig. l2, the left-hand end of the shaft 88 is rigidly connected to an externally threaded member 88, upon which a clutch member 89 is mounted, so that the member 89 turns in unison with the shaft 86.

The member 89 is provided with a cone or clutch surface which frictionally engages the gear 90. The gear 90 meshes with a screw 9|, which is turned by any suitable automatic mechanism. When the screw 9| is turned, this causes the gear 9D to turn, and the member 89 also turns in unison with the shaft 86.

Clutch member 89 is keyed to the hollow shaft 84.

The method of using the device is as follows:-

The shaft 3S is turned until the members 3l are in the position shown in Fig. 3.

A suitable length of steel strip is out off, by means of the blades 34a and 39h. This length of steel strip and the strip D are located within the holder 34, which is placed Within the members 31, While said members are in the vertical position illustrated in Fig. 3. The clamping members 35 and 31h are then in the position in which they do not clamp the thin steel strip or strip D. The ends of the flexible steel strip are engaged between the pairs of jaws 39 and 39a, and these pairs of jaws are moved away from each other so as to subject the steel strip to suitable tension and to hold the steel strip in tensed and planar condition.

The clamping members 35 and 31h are then operated so as to force -the jaws of the holder 34 against the blade D and its stiffening strip D.

After the blade D has thus been clamped so as to maintain it in the tensed and planar condition, the ends of the blade D are released from the jaws 39 and 39a. The shaft 38 is then turned to the position shown in Fig. 4. The worm le and the gear H are self-locking, so that the shaft 38 is held in the position to which it has been adjusted. The support S is now at one end of the machine, so that the parts may be moved to the position shown in Fig. 4.

The insert D may be located adjacent one face of the doctor blade D, so that the blade D is stiifened, save for the free outer edge-portion thereof.

When the parts are in the position shown in Fig. 4, only a narrow outer edge-portion of the blade D projects beyond the support 52 and the member D. The operator then moves the slide S by hand, or he connects the screw 9| to any suitable motor. The slide S is moved slowly in a longitudinal direction, while the shearing blade I8 is moved up and down with great rapidity by means of the motor M.

The vertically movable shearing blade I8 may have 1800 reciprocations per minute, and the slide S may be moved from one end to the other of a doctor blade having a length of 75 inches, during periods of 120 seconds.

The rapid shearing action, together with the use of the support 52, causes the edge of the blade D to be trimmed, without distorting the blade from true planar shape.

After the trimming has been completed, the blade and its holder 3d may be removed from the machine so that the trimmed blade can be used in the printing press.

The ordinary doctor blade has a Width of about three inches and the trimming action removes an outer edge portion of said blade having a width of about to 1% inch. The outer edge portion of the blade D projects beyond the support 52,1"or a width of about inch.

The lower shearing blade Il is maintained in contact with the bottom surface of the outer edge portion of the blade D, during the shearing operation, so that the vibrating cutting action of the blade I8 does not distort the blade D from true planar shape. If the doctor blade is made of a relatively heavy steel, about 0.014 inch thick, the use of the tensioning apparatus which includes jaws 39 and 39a, may be dispensed with. I have shown a preferred embodiment of my invention but it is clear that numerous changes and omissions can4 be made without departing from its spirit.

I claim:

l. A method of trimming the doctor blade of a printing press, said doctor blade being made of thin and resilient metal which has substantially no inherent rigidity, which consists in subjecting said doctor blade to tension and maintaining it in substantially planar form, and trimming the edge of the blade by means of a shearing action.

2. A method of trimming the doctor blade of a printing press, said doctor blade being made oi thin and resilient metal which has substantially no inherent rigidity, which consists in subjecting said doctor blade to tension and maintaining it in substantially planar form, and trimming the edge oi the blade by means of a shearing action, while rigidly supporting one surface of said edge close to the line of trimming, so that the ming is performed without substantially distorting the blade from said planar form.

3. Mechanism for trimming the doctor blade of a printing press, comprising means for supporting said doctor blade, a shearing device comprising a pair of blades, means for moving one of Said blades longitudinally relative to the blade, means for moving the other blade in said longitudinal direction and also in a direction lateral to said blade and in trimming relation to the edge of the blade.

4. Mechanism for trimming the doctor blade of a printing press, comprising turnable means adapted to support the doctor blade of the holder thereof, tensioning mechanism adapted to engage and tense said blade when said holder is in a predetermined position, said holder having means for clamping the blade while it is in tensed condition, said machine having an abutment adapted to contact with the blade when said turnable means are in a second predetermined position, and trimming means movable to trim the edge of said blade while the holding means are in the second mentioned position.

5. Mechanism for trimming the doctor blade of a printing press, comprising means for holding and supporting said doctor blade in planar shape, said means including a rigid abutment which is close to the free edge of the doctor blade and which contacts with a face of said doctor blade, a shearing device having superposed shearing members and means for operating the same, and a longitudinally movable support on which said shearing devicev is mounted, said longitudinally movable device being movable in a path which is close to said abutment and in a direction substantially parallel to the edge of the doctor blade, so that thefree edge of the doctor blade is iocated between said shearing members.

GUSTAVE A. FRIESS. 

